The present invention relates to certain novel antibiotics of the mureidomycin group, and also provides methods for preparing them and an antibacterial composition containing at least one of them as the active ingredient.
As resistance to conventional antibiotics becomes increasingly established in common strains of pathogenic bacteria, the need for a wider variety of antibiotics for use in the fight against such bacteria becomes ever more crucial. Although this need can be, and sometimes is, met by chemical modification of existing classes of antibiotics, the discovery of a wholly new class of antibiotics leads to exciting possibilities in the treatment of diseases caused by pathogenic bacteria.
Such a new class of antibiotics, named the "mureidomycins", is disclosed in our previous U.S. patent application Ser. No. 51,665 filed on May 18, 1987 and now abandoned which has been replaced by Continuation-in-part application Ser. No. 07/253,450 filed Oct. 4, 1988. In this we have disclosed the isolation of the first four members of this class, mureidomycins A, B, C and D, from the fermentation broth produced by a then newly discovered microorganism, Streptomyces flavidovirens SANK 60486 (BIKOKEN JOHKI 1347; FERM BP-1347).
We have now discovered two new members of this class of antibiotics, herein named "mureidomycins E and F", together with their salts and esters and certain other derivatives, which are particularly effective against Gram-negative bacteria, most especially strains of the genus Pseudomonas.
Mureidomycins E and F can also be isolated from the fermentation broth of Streptomyces strain SANK 60486. Alternatively, these two new mureidomycins, as well as certain of their derivatives, can be prepared by subjecting mureidomycin A to chemical reaction.
We have also discovered a further group of compounds, herein named "mureidomycins AP to FP", which are derivatives of and can be prepared from mureidomycins A to F, respectively. These compounds, and their salts and esters, are of use as synthetic intermediates in the preparation of other mureidomycins.